OsgiTestRunner launches Equinox, installs the project containing the testcase class as a bundle, starts the bundle, and then runs the testcase class from inside the bundle using a standard JUnit runner.

DmKernelTestRunner

The DmKernelTestRunner, which should probably be renamed to VirgoKernelTestRunner, is for testing components that need a Virgo kernel environment complete with kernel and user regions. It must be used in combination with suitable configuration to launch the kernel bundles and the bundle on which the kernel depends.